We have extended our research interest on titanium oxyphosphates (M^II(TiO)₂(PO₄)₂, with M^II = Mg, Fe, Co, Ni, Cu, Zn) to vanadium oxyphosphates M^II(V^IVO)₂(PO₄)₂ (M^II = Co, Ni). For each compound two phases, named α and β according to synthesis conditions, have been stabilized at room temperature, then characterized. The four crystal structures M(VO)₂(PO₄)₂ (α and β for M = Co, Ni) have been determined in monoclinic <i>P</i>2₁/<i>c</i> space group using X-ray single crystals diffraction data. Structure of the α phase is derived from the Li(TiO)(PO₄) (orthorhombic <i>Pnma</i>) and LiNi_0.50(TiO)₂(PO₄)₂ (monoclinic <i>P</i>2₁/<i>c</i>) types, with cell parameters: <i>a</i> = 6.310(1) Å, <i>b</i> = 7.273(1) Å, <i>c</i> = 7.432(1) Å, <i>β</i> = 90.43(1)° for M = Co, and <i>a</i> = 6.297(2) Å, <i>b</i> = 7.230(2) Å, <i>c</i> = 7.421(2) Å, <i>β</i> = 90.36(2)° for M = Ni. Structure of the β phase is derived from the Ni(TiO)₂(PO₄)₂-type (monoclinic <i>P</i>2₁/<i>c</i>) with cell parameters: <i>a</i> = 7.2742(2) Å, <i>b</i> = 7.2802(2) Å, <i>c</i> = 7.4550(2) Å, <i>β</i> = 120.171(2)° for M = Co, and <i>a</i> = 7.2691(2) Å, <i>b</i> = 7.2366(2) Å, <i>c</i> = 7.4453(2) Å, <i>β</i> = 120.231(2)° for M = Ni. All these structures consist of a three dimensional (3D) framework built up of infinite chains of tilted corner-sharing [VO₆] octahedra, cross-linked by corner-sharing [PO₄] tetrahedra. The M²⁺ ion (M = Co, Ni) is located in a triangular based antiprism which shares faces with two [VO₆] octahedra. Structural filiation is discussed based on a common structural unit, a sheet where divalent cations M²⁺ (M = Co, Ni) are inserted. A thermal study of the α ↔ β transition is also presented.< Leer menos